A computational study of the shear response and fracture resistance of the cytoskeleton of the single-celled organism Stentor

Creating synthetic systems that mimic life is a captivating research frontier. Yet, current synthetic cell studies overlook a key feature of life: resilience to physical damage. We probe the biomechanical defense mechanisms of the single-celled organism, Stentor, known for its ability to resist and rapidly heal from mechanical wounds. Here we focus on the Stentor's cytoskeleton, the polymeric scaffolding crucial for its integrity and rigidity. Based on Stentor electron microscopy images, we model its cytoskeleton as a composite network: parallel microtubule bundles (KM fibers) integrated with an underlying network that offers transverse connections and contractile elements (myonemes) that facilitate contraction of the KM fibers. We characterize the mechanical response of this network by calculating the shear modulus, fracture resistance, and spatial distribution of stresses for various densities and stiffnesses of KM fibers and the densities of myonemes. Our results shed light on potential cellular wound resilience mechanisms and suggest design principles for robust synthetic cells.